It's the second tragedy to have struck the close-knit family recently after his 18-year-old sister Caitlin died suddenly in February, just six months after the birth of her daughter.

He is also the son of 1998 murder victim John Knocker, who was gunned down outside the Exit 15 nightclub at the Glengannon Hotel in Dungannon, Co Tyrone.

It is understood the young Belfast man remains in a coma.

Local Sinn Fein councillor Steven Corr said the family have been moved by support from the public.

"There was a very good response for information to be brought forward and I think that's to be commended," he said.

"The family are overwhelmed by the level of support they have received about Ryan's health and messages of hope that he will pull through, and also for the people who came forward and gave statements. It gives the family a lot of solace and comfort that people have come forward and helps them in their time of need.

"The family have not left his side since it happened, they have been with him every step of the way. They are going through a lot. I believe there is some slight improvement, but he is still seriously ill."

A number of other politicians hit out at the stabbing including West Belfast SDLP MLA Alex Attwood, who said the community was in shock over the incident.

He said: "The thoughts of everyone in this community are with the victim's family and friends. Everybody hopes that the man, currently critically ill in hospital, makes a full recovery.

"As with all such incidents, local people are deeply upset. Everyone must now be focused on helping the police ensure that the full circumstances of this attack are investigated and appropriate action taken."

Another Sinn Fein councillor for the area, JJ Magee, also condemned the attack.

"It is my hope that he makes a full recovery from his injuries," he said.

"This attack followed a separate incident in north Belfast were a man was also attacked by a knife.

"I unreservedly condemn both attacks.

"Knives kill and using them as a weapon to attack someone often results in death or life-changing injuries, which has a wide-reaching impact on victims, their families and the wider community."